throw 404 when dataset is not available, compatibility fallback for o…

…ld narratives

cli/server/getDataset.js

@@ -12,7 +12,9 @@ const setUpGetDatasetHandler = ({datasetsPath}) => {
       await helpers.sendJson(res, info);
     } catch (err) {
       console.trace(err);
-      return helpers.handleError(res, `couldn't fetch JSONs`, err.message);
+      // Throw 404 when not available
+      const errorCode = err.message.endsWith("not in available datasets") ? 404 : 500;
+      return helpers.handleError(res, `couldn't fetch JSONs`, err.message, errorCode);
     }
   };
 };

cli/server/getDatasetHelpers.js

@@ -14,10 +14,10 @@ const path = require("path");
 const convertFromV1 = require("./convertJsonSchemas").convertFromV1;
 const fs = require("fs");
 
-const handleError = (res, clientMsg, serverMsg="") => {
+const handleError = (res, clientMsg, serverMsg="", code = 500) => {
   res.statusMessage = clientMsg;
   utils.warn(`${clientMsg} -- ${serverMsg}`);
-  return res.status(500).end();
+  return res.status(code).end();
 };
 
 const splitPrefixIntoParts = (url) => url

src/actions/loadData.js

@@ -27,8 +27,9 @@ const getDatasetFromCharon = (prefix, {type, narrative=false}={}) => {
   if (type) path += `&type=${type}`;
   const p = fetch(path)
     .then((res) => {
+      //throw the whole thing so we can check res.status
       if (res.status !== 200) {
-        throw new Error(res.statusText);
+        throw res;
       }
       return res;
     });
@@ -55,8 +56,9 @@ const getHardcodedData = (prefix, {type="mainJSON"}={}) => {
 
   const p = fetch(datapaths[type])
     .then((res) => {
+      //throw the whole thing so we can check res.status
       if (res.status !== 200) {
-        throw new Error(res.statusText);
+        throw res;
       }
       return res;
     });
@@ -265,12 +267,31 @@ const fetchAndCacheNarrativeDatasets = async (dispatch, blocks, query) => {
   // 2. allow loading dataset for secondTreeName
 
   // We block and await for the landing dataset
-  jsons[startingTreeName] = landingSlide.json = await getDataset(startingTreeName).then(((res) => res.json()));
+  jsons[startingTreeName] = landingSlide.json = await
+    getDataset(startingTreeName)
+      .then(res => res.json())
+      // If it's a 404 we fall back 
+      .catch((err) => {
+        if (err.status === 404) {
+          // Assuming block[0] is the one that was set properly for all legacy narratives
+          return getDataset(treeNames[0]);
+        } 
+        throw err;
+      });
 
   // The other datasets are fetched asynchronously
   for (const treeName of treeNames)
-  // With this there's no need for Set above
-    jsons[treeName] = jsons[treeName] || getDataset(treeName).then((res) => res.json());
+    // With this there's no need for Set above
+    jsons[treeName] = jsons[treeName] ||
+      getDataset(treeName)
+        .then((res) => res.json())
+        .catch((err) => {
+          if (err.status === 404) {
+            // We fall back to the landing slide
+            return jsons[startingTreeName];  
+          }
+          throw err;
+        });;
 
   // I don't think the below here is a real problem for any practical case (?)